Testing Batteries...

My father is working on a starting issue on a tractor for some one. The owner of the tractor had the starter off and repaired and the batteries removed and tested. Batteries tested good... I have had this happen to me as well. Where I suspect that I have a battery issue, I take the batteries off and have them tested only to have them test good at the store, they still do not work when installed in the machine. Also, when they are tested, I have noticed that the store personnel charge the batteries up first and then perform the test right after the charger is removed. This is when the battery tests good. However when I replace the battery or batteries, the issue goes a way. has any one else ran in to this issue??

Jared
 
A battery beginning to fail will show pretty good when fresh off of the charger. Testing a day later (disconnected but warm, will give a better impression of quality. Jim
 
Yes, that happens, especially if the battery is still under warranty.

A good DIY test is to charge the battery. At room temperature, the voltage will be 12.6 volts.

Leave the battery disconnected from the charger and the vehicle for a day or so, check the voltage. If it has dropped, the battery is failing.
 
Others are going to chime in. You need a load on the battery,not those magic boxes they use. That tester at Harbor Freight works quite well for around $30.oo, but the best is a full blown carbon loadtester for $50.oo. After you buy one and use it you will wonder how you lived without one in your shop. If you have an old school starter generator shop near you they should have one. Box stores have gizmos that idiots can use. MHO, I have two of the smaller ones and use them all over the place.
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I have seen ADs about a secret way to renew dead batteries. Almost always using Epsom salts. Do these really work? Has anyone ever tried it? Seems bogus to me.
 
One of those harbor freight battery load testers will pay for itself in the fuel you waste driving back and forth to the auto parts store to have them "test" the batteries.

Like others have said the only way to test a battery is to give it a good deep charge, then let it sit for a day before testing. What they do at the parts store is completely bogus. It can take up to 12 hours to fully charge a battery even at 10 Amps. Higher settings than 10A are for boosting the battery for a few minutes only, not long-term charging. You could boil off the electrolyte and damage the battery.
 
I had one like the top one. On my service truck. That is the only tester that really works. Puts a real load on a battery. Read the battery under load not just voltage. A battery can test good on voltage. But fail under load
 
The top one is good for 4 wheeler and lawn mower batteries but you need one like the bottom to put a load on a tractor battery.
 
Another test that works well is a voltage test while charging. I've some older Sun eqpt and the first test they suggest, before a good load test is done while boosting. A charger more than 25A is used and observe the voltage. It it stays below 15 volts, battery is ok for a load test. If it creeps up towards 20 volts, the battery is definitely bad and don't waste your time. I've found this to be a reliable test. Also, as mentioned below, quick charges are not good, and a small charger to restore a dead battery for a load test is best. I always use a trickle (3A) type charger to maintain and charge. It takes 24 hours but does a good job. Definitely use it once a month or so on eqpt not run very often. Also, as mentioned below, I use a piece of 1" dense Styrofoam (Pink stuff) under every battery, phenomenal in absorbing vibration which also is a battery killer
 
I should have said looked like that one. But it was made for the larger engines that I worked on. One of those will tell you if a battery is good or not. Very handy to have in the field. Since I didn't have room for the bigger units.
 
"One of those harbor freight battery load testers will pay for itself in the fuel you waste driving back and forth to the auto parts store to
have them "test" the batteries."

Amen brother!

I think mine was about 50 bucks and worth every penny. My pass-fail criteria is 200 amps and 11v battery terminal voltage. Sometimes on
batteries used for big diesels I'll run it on up to 300 amps for 10v. If they will hold that (for a couple of seconds max......things can get hot
really fast inside the unit) battery is good to go....give it a good recharge and worry about something else.
 
So far I have yet to see a Hydrometer show up here......that's where you start. If a cell is low you are already in trouble. Charge the battery, check the Sp. gravity then load test.
 
I have the second one like that top one and have no problem with being big enough for car, truck and tractor batteies. The first one went bad when it melted a connector inside but thsat was after several years. I knew battery was bad but my tester was saying good, took to store and their tester like mine was also saying good, took to different place and theirs said bad. I tore mine apart and found that connector had burnt, I had held the load test just a bit too long and I am sure that is what was with the store one that tested good. And if I want to know condition of battery I will load test first then try charge and test again. And by charger at max is only 8 amp.
 
Interesting you bring that up. I was looking for mine but could not find it. It's on the list. Great comment.

Paul
 
Re-Epson salts restore. I tried it on my pickup group 24 once. (self discharge] think it worked. excited, I treated some junk batteries I had. spent more on damaged coveralls, acid, etc than new batteries, might have helped one outa the bunch.
 

Batteries ain't what they used to be that's for sure!

As far as battery testers..I have a simple one like pictured that works well enough...and at least as good as the dealership or parts store testers.

I've found my 'Schumacher' (spelling?) battery charger does a pretty good job predicting bad batteries. I have a fancier MAC charger that does ok too.

You can't really test a battery effectively that's not charged. I use my Schumacher charger that tells you voltage and percent of charge on the display. Charge the battery and let it set for some time. Turn the charger back on and see if the battery held charge and voltage. Usually a bogus battery will fall back considerably from a fully charged battery.

Something else to consider....just because a battery is new is no certain guarantee that it is good!...I worked on a guy's 4430 that had newer/newish batteries and starter on it...genuine JD batteries. I rebuilt the left axel and planetary and had the tractor apart for about a month scrounging used parts(catastrophic failure)...Anyhow when I'm done with it I had to charge the batteries to get it started. No big deal except the next day it wouldn't start again....charged the batteries on low overnight..and no good!

I load test the fairly new Deere 'Strong-box' batteries and one is bad and one marginal. Take them to the Deere dealer and exchange them. Ehh..should be good huh?...Well no...the new Deere batteries are just as bad as the ones I exchanged...one tested bad and one marginal!!...Haul them back to Deere and the parts guy got smart and load-tested the new batteries before loading them in my truck...so essentially it took six JD batteries to get two good ones!!

Had the same thing happen to my service truck...installed a new battery and it didn't last a week...exchanged it and got a month or so out of the next battery...however the next new battery was fine and still going a couple years later.

Some guys recommend the dry cell 'Optima' batteries...but I've not had all that good a luck with those either. It really seems to me that one battery will do fine and last and last...while the next identical battery of what-ever brand will be jinxed!
 
The definitive test for a battery is to first charge it. A new battery that is discharged will fail a load test. Then use a high capacity carbon pile load tester. Load the battery for 15 seconds at half its CCA rating. A 1000 amp CCA would be tested at 500 amp load. After 15 seconds, the voltage must not drop below 9.6 volts. It takes a heavy duty tester to sufficiently load a big tractor battery. A hydrometer will tell if a battery is bad but not if it is good.
 
Hello buickanddere,

What! Volt test under actual operating-cranking conditions? That is a novel
idea! If we could instill the importance and simplicity of the use of a volt
meter.........

Guido.
 

Voltage across battery terminals vs voltage across starter main post to it's cast body. Battery voltage while cranking. Voltage measured across every joint or connection.
 
Hello Tech 7,

Hydrometer will measure individual cell state of charge,useless!. Think about this: Suppose you measure each cell at they are fully charged, and just one of the cells connecting straps was not making connection, zero voltage across the dead battery posts. A load test would show the battery capacity, or the lack of,

Guido.
 
Hello Leroy,

You know that a battery load test is performed @ 1/2 the battery CCA of CA rating right? The top tester is a 100amp load tester. A lawn mower battery is at least 235CCA.
The top one would not do! But it will certainly shows that you have a good battery. Now you go chase ghosts,

Guido.
 

I would like to know how in the ell came up with let the battery set a day before you load test it is this to increase the misery...

It sure as ell is not practical! If so tell me were you are lost are don't know what you are doing...

Hydrometer you have time on your hands to waist it proves nuttin a load test wont prove RAT NOW...
 
Hello Janicholson,

That is not correct! What mechanic has a day to wait when trying to get a vehicle started? Industry's battery testing standard calls for fully charging the battery first. Then taking the surface charge down by loading it for 5 seconds. Then when the tool cools for a minute or so perform the standard test. 1/2 CCA load for 15 seconds. Passing voltage is a minimum of 9.6 volts.....

Guido.
 

Somewhere in my collection of books I have instructions on how to make your own lead-acid battery in a wooden box. Be interesting to see how it actually worked.
 

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